defmodule BeamFile do
@moduledoc """
An interface to the BEAM file format.
This module is mainly a wrapper around Erlangs `:beam_lib`.
For more information see the Erlang documenation for the module
[`beam_lib`](https://www.erlang.org/doc/man/beam_lib.html)
Furthermore, different code representations can be generated from the file.
- `BeamFile.abstract_code/1`
- `BeamFile.byte_code/1`
- `BeamFile.erl_code/1`
- `BeamFile.elixir_code/2`
To use the functions above with a module name the module must be compiled
and loaded. The functions can also be used with the binary of a module.
"""
alias BeamFile.Error
@type info :: [
file: Path.t() | binary(),
module: module(),
chunks: [{charlist(), non_neg_integer(), non_neg_integer()}]
]
@type path :: charlist()
@type input :: path() | module() | binary()
@type reason :: any()
@typedoc """
Chunk ID.
```
'Abst'
| 'Attr'
| 'AtU8'
| 'CInf'
| 'Dbgi'
| 'Dcos'
| 'ExCk'
| 'ExpT'
| 'ImpT'
| 'LocT'
```
"""
@type chunk_id :: charlist()
@type chunk_name ::
:abstract_code
| :atoms
| :attributes
| :compile_info
| :debug_info
| :docs
| :elixir_checker
| :exports
| :imports
| :indexed_imports
| :labeled_exports
| :labeled_locals
| :locals
@type chunk_ref :: chunk_name | chunk_id
@chunk_ids [
'Abst',
'AtU8',
'Attr',
'CInf',
'Dbgi',
'Docs',
'ExCk',
'ExpT',
'ImpT',
'LocT'
]
@chunk_names [
:abstract_code,
:atoms,
:attributes,
:compile_info,
:debug_info,
:docs,
:elixir_checker,
:exports,
:imports,
:indexed_imports,
:labeled_exports,
:labeled_locals,
:locals
]
@default_lang "en"
@blank " "
@new_line "\n"
@new_paragraph "\n\n"
@doc_ -2
# @spec_ -1
@fun 0
@args 1
@super 2
@guards 3
@block 4
@doc """
Returns the `:abstract_code` chunk.
## Examples
iex> BeamFile.abstract_code(BeamFile.Example)
{:ok,
[
{:attribute, 1, :file, {'test/fixtures/example.ex', 1}},
{:attribute, 1, :module, BeamFile.Example},
{:attribute, 1, :compile, [:no_auto_import]},
{:attribute, 1, :export, [__info__: 1, hello: 0]},
{:attribute, 1, :spec,
{{:__info__, 1},
[
{:type, 1, :fun,
[
{:type, 1, :product,
[
{:type, 1, :union,
[
{:atom, 1, :attributes},
{:atom, 1, :compile},
{:atom, 1, :functions},
{:atom, 1, :macros},
{:atom, 1, :md5},
{:atom, 1, :exports_md5},
{:atom, 1, :module},
{:atom, 1, :deprecated}
]}
]},
{:type, 1, :any, []}
]}
]}},
{:function, 0, :__info__, 1,
[
{:clause, 0, [{:atom, 0, :module}], [], [{:atom, 0, BeamFile.Example}]},
{:clause, 0, [{:atom, 0, :functions}], [],
[{:cons, 0, {:tuple, 0, [{:atom, 0, :hello}, {:integer, 0, 0}]}, {nil, 0}}]},
{:clause, 0, [{:atom, 0, :macros}], [], [nil: 0]},
{:clause, 0, [{:atom, 0, :exports_md5}], [],
[
{:bin, 0,
[
{:bin_element, 0,
{:string, 0,
[240, 105, 247, 119, 22, 50, 219, 207, 90, 95, 127, 92, 159, 46, 131, 169]},
:default, :default}
]}
]},
{:clause, 0, [{:match, 0, {:var, 0, :Key}, {:atom, 0, :attributes}}], [],
[
{:call, 0, {:remote, 0, {:atom, 0, :erlang}, {:atom, 0, :get_module_info}},
[{:atom, 0, BeamFile.Example}, {:var, 0, :Key}]}
]},
{:clause, 0, [{:match, 0, {:var, 0, :Key}, {:atom, 0, :compile}}], [],
[
{:call, 0, {:remote, 0, {:atom, 0, :erlang}, {:atom, 0, :get_module_info}},
[{:atom, 0, BeamFile.Example}, {:var, 0, :Key}]}
]},
{:clause, 0, [{:match, 0, {:var, 0, :Key}, {:atom, 0, :md5}}], [],
[
{:call, 0, {:remote, 0, {:atom, 0, :erlang}, {:atom, 0, :get_module_info}},
[{:atom, 0, BeamFile.Example}, {:var, 0, :Key}]}
]},
{:clause, 0, [{:atom, 0, :deprecated}], [], [nil: 0]}
]},
{:function, 2, :hello, 0, [{:clause, 2, [], [], [{:atom, 2, :world}]}]}
]}
"""
@spec abstract_code(input()) :: {:ok, term()} | {:error, any()}
def abstract_code(input) do
with {:ok, {:raw_abstract_v1, abstract_code}} <- chunk(input, :abstract_code) do
{:ok, abstract_code}
end
end
@doc """
Same as `abstract_code/1` but raises `BeamFile.Error`
"""
@spec abstract_code!(input()) :: term()
def abstract_code!(input) do
case abstract_code(input) do
{:ok, abstract_code} ->
abstract_code
{:error, reason} ->
raise Error, """
Abstract code for #{inspect(input, binaries: :as_binaries)} not available, \
reason: #{inspect(reason, binaries: :as_binaries)}\
"""
end
end
@doc """
Returns chunk data for all chunks.
The `type` argument forces the use of `:ids` or `:names`, defaults to `:names`.
## Examples
iex> {:ok, chunks} = BeamFile.all_chunks(BeamFile.Example, :names)
iex> chunks |> Map.keys() |> Enum.sort()
[
:abstract_code,
:atoms,
:attributes,
:compile_info,
:debug_info,
:docs,
:elixir_checker,
:exports,
:imports,
:indexed_imports,
:labeled_exports,
:labeled_locals,
:locals
]
iex> Map.get(chunks, :docs)
{:docs_v1, 1, :elixir, "text/markdown", :none, %{},
[{{:function, :hello, 0}, 2, ["hello()"], :none, %{}}]}
iex> {:ok, chunks} = BeamFile.all_chunks(BeamFile.Example, :ids)
iex> chunks |> Map.keys() |> Enum.sort()
['Abst', 'AtU8', 'Attr', 'CInf', 'Dbgi', 'Docs', 'ExCk', 'ExpT', 'ImpT', 'LocT']
iex> chunks |> Map.get('Docs') |> is_binary()
true
"""
@spec all_chunks(input(), type :: :names | :ids) :: {:ok, map()} | {:error, any()}
def all_chunks(input, type \\ :names)
def all_chunks(input, type) when is_atom(input) and type in [:ids, :names] do
with {:ok, path} <- path(input) do
all_chunks(path, type)
end
end
def all_chunks(input, type) when type in [:ids, :names] do
chunks =
case type do
:names -> @chunk_names
:ids -> @chunk_ids
end
fetch_chunks(input, chunks, type)
end
@doc """
Same as `all_chunks/` but raises `BeamFile.Error`
"""
@spec all_chunks!(input(), type :: :names | :ids) :: map
def all_chunks!(input, type \\ :names) do
case all_chunks(input, type) do
{:ok, chunks} ->
chunks
{:error, reason} ->
raise Error, """
Chunks for #{inspect(input, binaries: :as_binaries)} not available, \
reason: #{inspect(reason, binaries: :as_binaries)}\
"""
end
end
@doc """
Returns the byte code for the BEAM file.
## Examples
iex> {:ok, byte_code} = BeamFile.byte_code(BeamFile.Example)
iex> byte_code |> Tuple.to_list() |> Enum.take(3)
[
:beam_file,
BeamFile.Example,
[{:__info__, 1, 2}, {:hello, 0, 9}, {:module_info, 0, 11}, {:module_info, 1, 13}]
]
"""
@spec byte_code(input()) :: {:ok, term()} | {:error, any()}
def byte_code(input) when is_atom(input) do
with {:ok, path} <- path(input), do: byte_code(path)
end
def byte_code(input) when is_list(input) or is_binary(input) do
with {:ok, data} <- read(input) do
case :beam_disasm.file(data) do
{:error, :beam_lib, reason} -> {:error, reason}
byte_code -> {:ok, byte_code}
end
end
end
@doc """
Same as `byte_code/1` but raises `BeamFile.Error`
"""
@spec byte_code!(input()) :: term()
def byte_code!(input) do
case byte_code(input) do
{:ok, byte_code} ->
byte_code
{:error, reason} ->
raise Error, """
Byte code for #{inspect(input, binaries: :as_binaries)} not available, \
reason: #{inspect(reason, binaries: :as_binaries)}\
"""
end
end
@doc """
Returns infos for the given chunk reference.
## Examples
iex> BeamFile.chunk(BeamFile.Example, :exports)
{:ok, [__info__: 1, hello: 0, module_info: 0, module_info: 1]}
iex> {:ok, chunk} = BeamFile.chunk(BeamFile.Example, 'Dbgi')
iex> is_binary(chunk)
true
"""
@spec chunk(input(), chunk_ref()) :: {:ok, term()} | {:error, any()}
def chunk(input, chunk)
when is_atom(input) and (chunk in @chunk_ids or chunk in @chunk_names) do
with {:ok, path} <- path(input), do: chunk(path, chunk)
end
def chunk(input, chunk)
when (is_list(input) or is_binary(input)) and
(chunk in @chunk_ids or chunk in @chunk_names) do
type =
cond do
chunk in @chunk_names -> :names
chunk in @chunk_ids -> :ids
end
with {:ok, data} <- fetch_chunks(input, [chunk], type) do
[{_key, value}] = Map.to_list(data)
{:ok, value}
end
end
@doc """
Same as `chunk/2` but raises `BeamFile.Error`
"""
@spec chunk!(input(), chunk_ref()) :: term
def chunk!(input, chunk) do
case chunk(input, chunk) do
{:ok, data} ->
data
{:error, reason} ->
raise Error, """
Chunk #{inspect(chunk)} for #{inspect(input, binaries: :as_binaries)} not available, \
reason: #{inspect(reason, binaries: :as_binaries)}\
"""
end
end
@doc """
Returns the infos from the `:debug_info` chunk.
Examples:
iex> {:ok, info} = BeamFile.debug_info(BeamFile.Example)
iex> Map.get(info, :definitions)
[{{:hello, 0}, :def, [line: 2], [{[line: 2], [], [], :world}]}]
iex> Map.get(info, :relative_file)
"test/fixtures/example.ex"
"""
@spec debug_info(input()) :: {:ok, term()} | {:error, any}
def debug_info(input) when is_atom(input) do
with {:ok, path} <- path(input) do
debug_info(path)
end
end
def debug_info(input) when is_list(input) or is_binary(input) do
with {:ok, {:debug_info_v1, backend, data}} <- chunk(input, :debug_info) do
case data do
{:elixir_v1, debug_info, _meta} ->
backend.debug_info(:elixir_v1, debug_info.module, data, [])
:none ->
{:error, :no_debug_info}
end
end
end
@doc """
Same as `debug_info/1` but raises `BeamFile.Error`
"""
@spec debug_info!(input()) :: term()
def debug_info!(input) do
case debug_info(input) do
{:ok, debug_info} ->
debug_info
{:error, reason} ->
raise Error, """
Debug info for #{inspect(input, binaries: :as_binaries)} not available, \
reason: #{inspect(reason, binaries: :as_binaries)}\
"""
end
end
@doc """
Returns the infos from the `:docs` chunk.
## Examples
iex> BeamFile.docs(BeamFile.Example)
{:ok, {:none, %{}, [{{:function, :hello, 0}, 2, ["hello()"], :none, %{}}]}}
"""
@spec docs(input()) :: {:ok, term()} | {:error, any}
def docs(input) when is_atom(input) do
with {:ok, path} <- path(input) do
docs(path)
end
end
def docs(input) when is_list(input) or is_binary(input) do
with {:ok, {:docs_v1, _, :elixir, "text/markdown", doc, meta, docs}} <- chunk(input, :docs) do
{:ok, {doc, meta, docs}}
end
end
@doc """
Same as `docs/1` but raises `BeamFile.Error`
"""
@spec docs!(input()) :: term()
def docs!(input) do
case docs(input) do
{:ok, docs} ->
docs
{:error, reason} ->
raise Error, """
Docs for #{inspect(input, binaries: :as_binaries)} not available, \
reason: #{inspect(reason, binaries: :as_binaries)}\
"""
end
end
@doc ~S'''
Returns elixir code recreated from the `debug_info` chunk.
The recreated code comes with resolved macros and references.
For now, types and specs will not be recreated.
Options:
`:docs`: With `docs: false` the docs will not be created.
## Examples
iex> BeamFile.elixir_code(BeamFile.Example)
{
:ok,
"""
defmodule Elixir.BeamFile.Example do
def hello do
:world
end
end\
"""
}
'''
@spec elixir_code(input(), opts :: keyword()) :: {:ok, String.t()} | {:error, any}
def elixir_code(input, opts \\ [])
def elixir_code(input, opts) when is_atom(input) do
with {:ok, path} <- path(input) do
elixir_code(path, opts)
end
end
def elixir_code(input, opts) when is_list(input) or is_binary(input) do
with {:ok, debug_info} <- debug_info(input) do
code =
debug_info
|> definitions()
|> docs(input, opts)
|> to_code(debug_info)
{:ok, code}
end
end
@doc """
Same as `eleixir_code/1` but raises `BeamFile.Error`
"""
@spec elixir_code!(input(), opts :: keyword()) :: String.t()
def elixir_code!(input, opts \\ []) do
case elixir_code(input, opts) do
{:ok, code} ->
code
{:error, reason} ->
raise Error, """
Elixir code for #{inspect(input, binaries: :as_binaries)} not available, \
reason: #{inspect(reason, binaries: :as_binaries)}\
"""
end
end
@doc """
Returns the Erlang code for the BEAM file.
## Examples
iex> {:ok, code} = BeamFile.erl_code(BeamFile.Example)
iex> code =~ "-module('Elixir.BeamFile.Example')"
true
"""
@spec erl_code(input()) :: {:ok, String.t()} | {:error, any()}
def erl_code(input) when is_atom(input) do
with {:ok, path} <- path(input) do
erl_code(path)
end
end
def erl_code(input) when is_list(input) or is_binary(input) do
with {:ok, abstract_code} <- abstract_code(input) do
code =
abstract_code
|> :erl_syntax.form_list()
|> :erl_prettypr.format()
|> to_string()
{:ok, code}
end
end
@doc """
Same as `erl_code/1` but raises `BeamFile.Error`
"""
@spec erl_code!(input()) :: String.t()
def erl_code!(input) do
case erl_code(input) do
{:ok, code} ->
code
{:error, reason} ->
raise Error, """
Erlang code for #{inspect(input, binaries: :as_binaries)} not available, \
reason: #{inspect(reason, binaries: :as_binaries)}\
"""
end
end
@doc """
Returns the binary for the given BEAM file.
"""
@spec read(Path.t() | path() | module()) ::
{:ok, binary()}
| {:error, File.posix()}
| {:error, :non_existing | :preloaded | :cover_compiled}
def read(input) when is_binary(input), do: {:ok, input}
def read(input) when is_list(input) do
input |> List.to_string() |> File.read()
end
def read(input) when is_atom(input) do
with {:ok, path} <- which(input), do: path |> String.to_charlist() |> read()
end
@doc """
Same as `read/1` but raises `BeamFile.Error`
"""
@spec read!(input()) :: binary()
def read!(input) do
case read(input) do
{:ok, binary} ->
binary
{:error, reason} ->
raise Error, """
Can not read #{inspect(input, binaries: :as_binaries)}, \
reason: #{inspect(reason, binaries: :as_binaries)}\
"""
end
end
@doc """
Returns `true` if a BEAM file for the given `module` exists.
## Examples
iex> BeamFile.exists?(BeamFile.Example)
true
iex> BeamFile.exists?(Physics.TOE)
false
"""
@spec exists?(module()) :: boolean()
def exists?(module) do
case :code.which(module) do
:non_existing -> false
[] -> false
_path -> true
end
end
@doc """
Returns a keyword list containing some information about a BEAM file.
- `:file`: The name of the BEAM file, or the binary from which the information
was extracted.
- `:module`: The name of the module.
- `:chunks`: For each chunk, the identifier and the position and size of the
chunk data, in bytes.
## Examples
iex> {:ok, info} = BeamFile.info(BeamFile.Example)
iex> info[:module]
BeamFile.Example
iex> info[:chunks]
...> |> Enum.map(fn {id, _pos, _size} -> id end)
...> |> Enum.sort()
[
'AtU8',
'Attr',
'CInf',
'Code',
'Dbgi',
'Docs',
'ExCk',
'ExpT',
'ImpT',
'Line',
'LitT',
'LocT',
'StrT'
]
"""
@spec info(input()) :: {:ok, info()} | {:error, reason()}
def info(input) when is_atom(input) do
with {:ok, path} <- path(input), do: info(path)
end
def info(input) when is_list(input) do
case :beam_lib.info(input) do
{:error, :beam_lib, reason} ->
{:error, reason}
info ->
info = Keyword.put(info, :file, IO.chardata_to_string(input))
{:ok, info}
end
end
def info(input) when is_binary(input) do
case :beam_lib.info(input) do
{:error, :beam_lib, reason} -> {:error, reason}
info -> {:ok, info}
end
end
@doc """
Returns the absolute filename for the `module`.
If the module cannot be found, `{:error, :non_existing}` is returned.
If the module is preloaded, `{:error, :preloaded}` is returned.
If the module is Cover-compiled, `{:error, :cover_compiled}` is returned.
## Examples
iex> {:ok, path} = BeamFile.which(BeamFile.Example)
iex> path =~ "/_build/test/lib/beam_file/ebin/Elixir.BeamFile.Example.beam"
"""
@spec which(module()) ::
{:ok, Path.t()}
| {:error, :non_existing | :preloaded | :cover_compiled}
def which(module) when is_atom(module) do
case :code.which(module) do
[_ | _] = path -> {:ok, IO.chardata_to_string(path)}
[] -> {:error, :non_existing}
error -> {:error, error}
end
end
@doc """
Same as `which/1` but raises `BeamFile.Error`
"""
@spec which!(module()) :: Path.t()
def which!(module) when is_atom(module) do
case which(module) do
{:ok, path} ->
path
{:error, reason} ->
raise Error, "Path for #{module} not available, reason: #{inspect(reason)}."
end
end
defp fetch_chunks(input, chunks, type) when type in [:ids, :names] do
chunks = Enum.map(chunks, &to_erl_chunk/1)
case :beam_lib.chunks(input, chunks, [:allow_missing_chunks]) do
{:ok, {_module, data}} ->
data = Enum.into(data, %{}, fn item -> to_elixir_data(item, type) end)
{:ok, data}
{:error, :beam_lib, reason} ->
{:error, reason}
end
end
# Some chunks are not available via a chunk-name. For this chunks we need the
# chunk-id.
defp to_erl_chunk(:docs), do: 'Docs'
defp to_erl_chunk(:elixir_checker), do: 'ExCk'
defp to_erl_chunk(chunk), do: chunk
# For some chunks we need a transformation.
defp to_elixir_data({'Docs', data}, :names), do: {:docs, :erlang.binary_to_term(data)}
defp to_elixir_data({'ExCk', data}, :names), do: {:elixir_checker, :erlang.binary_to_term(data)}
defp to_elixir_data({'Docs', data}, :ids), do: {'Docs', data}
defp to_elixir_data({'ExCk', data}, :ids), do: {'ExCk', data}
defp to_elixir_data(item, _type), do: item
defp path(module) when is_atom(module) do
case :code.which(module) do
[] -> {:error, :non_existing}
[_ | _] = path -> {:ok, path}
error -> {:error, error}
end
end
defp definitions(%{definitions: definitions}) do
definitions
|> Enum.with_index()
|> Enum.flat_map(fn {{{name, _arity}, kind, _meta, clauses}, def_index} ->
clauses
|> Enum.with_index()
|> Enum.flat_map(fn {{meta, args, guards, block}, clause_index} ->
index = def_index + clause_index / (length(clauses) + 1)
meta =
meta
|> Keyword.put(:name, name)
|> Keyword.put(:kind, kind)
[
fun(meta, index),
args(args, meta, index),
guards(guards, meta, index),
block(block, meta, index)
]
end)
end)
end
defp fun(meta, index) do
line = line(meta)
kind = meta[:kind]
name = meta[:name]
code = [to_string(kind), @blank, to_string(name)]
{code, {line, index, @fun}}
end
defp args(args, meta, index) do
line = line(meta)
code =
args
|> Enum.map(&code_to_string/1)
|> case do
[] -> @blank
code -> ["(", Enum.join(code, ", "), ")", @blank]
end
{code, {line, index, @args}}
end
defp guards([], _, _), do: :none
defp guards(guards, meta, index) do
line = line(meta)
code = Enum.map(guards, &code_to_string/1)
{[@blank, "when ", code, @blank], {line, index, @guards}}
end
defp block({:__block__, [], block}, meta, index), do: do_block(block, meta, index)
defp block({:super, context, args}, meta, index) do
line = line(meta)
code = code_to_string({meta[:name], context, args})
code = ["do", @new_line, code, @new_line, "end", @new_paragraph]
{code, {line, index, @super}}
end
defp block(block, meta, index) do
line = line(meta)
code = ["do", @new_line, code_to_string(block), @new_line, "end", @new_paragraph]
{code, {line, index, @block}}
end
defp do_block(block, meta, index) when is_list(block) do
line = line(meta)
code = Enum.map_join(block, @new_line, &code_to_string/1)
code = ["do", @new_line, code, @new_line, "end", @new_paragraph]
{code, {line, index, @block}}
end
defp docs(code, module, opts) do
with {:docs, true} <- {:docs, Keyword.get(opts, :docs, true)},
{:ok, docs} <- docs(module) do
Enum.concat([
code,
moduledoc(docs),
fundocs(docs)
])
else
_ -> code
end
end
defp fundocs({_doc, _meta, []}), do: [:none]
defp fundocs({_doc, _meta, docs}) do
Enum.map(docs, fn
{_fun, _line, _code, :none, _meta} ->
:none
{_fun, _line, _code, :hidden, _meta} ->
:none
{_fun, line, _code, doc, _meta} ->
case Map.fetch(doc, @default_lang) do
:error ->
:none
{:ok, doc} ->
doc = """
@doc \"""
#{doc}
\"""
"""
{doc, {line, 0, @doc_}}
end
end)
end
defp moduledoc({doc, _, _}) when doc in [:none, :hidden], do: [:none]
defp moduledoc({doc, _, _}) do
case Map.fetch(doc, @default_lang) do
{:ok, str} ->
str = """
\"""
#{str}
\"""
"""
code = ["@moduledoc", @blank, str, @new_paragraph]
{code, {0, 0, @doc_}}
:error ->
:none
end
|> List.wrap()
end
defp line(meta), do: Keyword.get(meta, :line, 0)
defp code_to_string(code), do: Macro.to_string(code)
defp to_code(data, debug_info) do
module = Map.get(debug_info, :module) |> to_string()
code =
data
|> Enum.filter(fn
:none -> false
_ -> true
end)
|> sort()
|> strip()
|> IO.iodata_to_binary()
"""
defmodule #{module} do
#{code}
end
"""
|> Code.format_string!()
|> IO.iodata_to_binary()
end
defp sort(data) do
Enum.sort(data, fn
{_, {line, index, ord_a}}, {_, {line, index, ord_b}} -> ord_a <= ord_b
{_, {line, index_a, _}}, {_, {line, index_b, _}} -> index_a <= index_b
{_, {line_a, _, _}}, {_, {line_b, _, _}} -> line_a <= line_b
end)
end
defp strip(data), do: Enum.map(data, fn {iodata, _} -> iodata end)
end
